Those who have ridden in many parts in New Mexico will usually agree that the mountain biking in the Taos area is probably the best the state has to offer. There are high alpine meadows and scorching desert rides and everything in between - and Eske's Brewpub for some post-ride recovery fluids . The South Boundary Trail - usually rated as one the top 10 rides in the country runs from Black Lake (near Angel Fire) and ends 25 miles later in Taos. Of all the trails I've ridden over the past 15 years or so, the SB ranks 1st on my list for an "overall" bad-ass ride. Monarch Crest in Salida CO is a better "ride" but the amount of people on that trail ruins it. Porcupine Rim in Moab is another great ride that I would rank a tad higher than the SB, but again, the amount of people out there just kills it.
You will be very lucky to see 10 people on the SB - and most of those will be at the end of the trail near Taos. The typical way to do this ride is to shuttle over to Black Lake, ride the Forest Service road to Osha Pass and cruise to 20 or so (mostly downhill) miles back to Taos. Since I usually do this
ride on my own I will ride it as an out-and-back (usually not all the way out). Since the last few miles of the SB (just outside of Taos) are pretty loose and steep, I usually take a side trail (Ojito) up to a point where it hooks in with the SB. Although there are a few technical sections on the SB - it's really known for it's fast, smooth and swoopy singletrack. Fall is a great
time to do this ride when all the aspens are changing.